Climate change and the northward shift of Cryptotympana facialis in Japan: evidence from national survey data

Masayuki U. Saito*, Osamu Kurashima, Motomi Ito

ABSTRACT: We developed a species distribution model of Cryptotympana facialis in Japan in order to investigate (1) the relationship between climate change and the northward shift of this species, (2) the existence of potential habitats in northern areas, and (3) the possibility of further northward shifts in the future. The distribution of C. facialis can be explained by life-history-related climate factors, including egg-hatching probability based on the sum of effective temperature, total precipitation during the rainy season, topographic slope, and the proportions of forest and urban areas, using an intrinsic Gaussian conditional autoregressive (CAR) model. The changes in potential habitat for C. facialis under climate change were projected using predicted climate conditions for 2070. In the parameter estimates of the CAR model, hatching probability, precipitation, and urban area were positive factors, while slope and forest area were negative factors. The fixed effects of the CAR model showed that more potential habitats exist in the north than in the current range of the species in western Japan. Moreover, our projection showed areas of suitable habitat increasing under all climate change scenarios. The current distribution of C. facialis is not in a state of equilibrium, possibly due to its low speed of dispersal. The distribution of C. facialis will expand to northern areas without climate warming, but climate warming will increase the amount of potential habitat. We emphasize the importance of considering life-history-related climatic factors, non-climatic factors, and spatial autocorrelation when modeling species distributions under climate change.